Preliminary Investigations of Sandhill Crane Feather Analysis

Abstract

Primary feathers from captive sandhill cranes (Grus canadensis) were subjected to quantitative chemical analysis (atomic absorption and flame emission) to determine if plumage mineralization could be used to identify the natal areas of these birds. The experiment was designed to test whether chemical differences existed between the plumage of males and females, juveniles and adults, and among the primary feathers 1, 5, and 10. The mineral elements Ca, Cu, Fe, Mg, Mn, K, Na, and Zn were used as variables. Feathers from Japanese (G. japonensis), sarus (G. antigone), common (Q. grus), and crowned (Balearica spp.) cranes were also analysed to test for interspecies mineral differences. Mineral differences (P<0.05) occurred between sexes for copper (primary-1) and zinc (primary-5) and for nearly all mineral elements in the primary-1 and -5 analysis between juvenile (one year old) and adult birds. Age and sex related mineral differences did not occur in the primary-10 analysis. Differences among primaries-1, -5, and -10 occurred for all variables except copper and sodium. The analysis of element ratios showed age and sex differences in the primary-1 and -5 analysis but no differences (P>0.05) in the primary-10 analysis. The variables Ca, Cu, and Mg showed the largest between­ species differences with Ca exhibiting the greatest variation (P<0.01). Ca and Mg values ranged from high to low in the crowned, common, sarus, sandhill, and Japanese cranes respectively. The Ca concentration in the crowned crane feathers was almost twice that of the other species. The analyses indicate that interspecies feather mineral differences do exist, however, the causes underlying these differences were not identified. Feathers collected from wild sandhill cranes in Wisconsin, Michigan, and Canada showed that feather mineral patterns reflected the geochemical environments of the respective natal areas. Small sample sizes precluded the use of statistical testing, however, characteristic mineral patterns could be seen in the ionic diagrams from each natal area. Feather mineral variation between sexes, age classes, and primary feathers indicates the need for a standardization scheme. A standard cohort, e.g., adult breeder, and a standard primary, e.g., number 10 from birds of both known (reference) and unknown natal areas should be used.